Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 AM EST Tue Nov 17 2015 Valid 12Z Tue Nov 17 2015 - 12Z Thu Nov 19 2015 ...Severe thunderstorms and flash flooding possible across portions of the southern plains and Mississippi valley... ...Winter storm to bring heavy snow and strong winds to portions of the central plains... ...Unsettled conditions to continue for the northwestern U.S... A strong and expansive storm system will bring a variety of weather conditions to the central U.S. today. A surface low pressure system is deepening across the southern plains this morning as a vigorous upper-level disturbance moves from the Four Corners region into the southern plains. Showers and thunderstorms are occurring this morning ahead of the cold front across the southern plains, and these will continue today as the cold front moves eastward into the lower Mississippi valley by this evening. The Storm Prediction Center is once again forecasting a slight to enhanced risk of severe thunderstorms today across portions of the southern plains and lower Mississippi valley. Additionally, heavy rainfall amounts of 2 to 4 inches are forecast across areas from the southern plains to the lower and mid-Mississippi valley, and flash flooding is possible. The frontal system will move east on Wednesday, bringing showers and thunderstorms to the Ohio valley and southeastern U.S., reaching the Eastern Seaboard by early Thursday morning. Heavy rain will still be possible on Wednesday, with flash flooding possible across portions of the southeastern U.S. and southern Appalachians. On the northwest side of the low pressure system across the plains, cold air will be pulled southward into the system, changing rain to snow from eastern Colorado into the central High Plains this morning. The dynamic nature of the storm system will allow for snow to fall heavily at times, and snowfall amounts of 6 to 12 inches are forecast in a band from east central Colorado into northwestern Kansas and southwestern Nebraska. Additionally, strong gusty winds of 30 to 40 mph, with gusts in excess of 50 mph will be possible in some areas, resulting in blizzard conditions. Snow is forecast to taper off across these areas tonight as the low pressure system lifts northward into the Upper Midwest. The weather pattern will also remain active across the northwestern U.S., with a series of Pacific storm systems set to affect the region. One such frontal system will move inland in the Northwest today, bringing potentially heavy rainfall to coastal areas. Rain will change to snow this evening in the Cascades as the cold front passes. Mountain snow and valley rain are also in the forecast across the northern Intermountain West today in association with this system. Yet another low pressure system will approach the Northwest Wednesday night, once again spreading rain and mountain snows into the Northwestern U.S. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php